Unfortunately his old visa is now void and he will be on a visa exemption. He will have to reapply for non O and put the 800,000 in for the 1st year. His history counts for nothing. I know because we forgot to get a re-entry stamps once & had to go through the whole process again despite having lived here for 9 years previously on a Non O. An agent may be able to help in this case...good luck
Just remember to get a re entry permit each time or buy a multiple re entry stamp if you intend to travel a lot. If you forget to buy you lose your visa and have to start again! (Spoken from experience even after living here 10 years! I'd had a stressful year & simply forgot)